Hydrangea plant named ‘Dardom’

ABSTRACT

A distinct cultivar of Hydrangea plant named ‘Dardom’, characterized by its large and vigorous growth habit; upright and rounded plant habit; strong stems; large durable leaves; large dome-shaped inflorescences; and inflorescences with large sterile flowers and numerous small fertile flowers.

Botanical classification/cultivar designation: Hydrangea arborescenscultivar Dardom.

BACKGROUND OF THE INVENTION

The present Invention relates to a new and distinct cultivar ofHydrangea plant, botanically known as Hydrangea arborescens, andhereinafter referred to by the cultivar name Dardom.

The new Hydrangea originated from a chance cross-pollination in 1997 oftwo unidentified selections of Hydrangea arborescens, not patented. Thecultivar Dardom was discovered and selected by the Inventor as a singleplant within the progeny of the stated cross-pollination in a controlledenvironment in Essen, Belgium.

Asexual reproduction of the new cultivar by softwood cuttings taken atLeersum, The Netherlands, since spring, 1999, has shown that the uniquefeatures of this new Hydrangea are stable and reproduced true to type insuccessive generations.

SUMMARY OF THE INVENTION

Plants of the cultivar Dardom have not been observed under all possibleenvironmental conditions. The phenotype may vary somewhat withvariations in environment such as temperature and light intensitywithout, however, any variance in genotype.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘Dardom’. These characteristics incombination distinguish ‘Dardom’ as a new and distinct cultivar:

1. Large and vigorous growth habit.

2. Upright and rounded plant habit, strong stems.

3. Large durable leaves.

4. Large dome-shaped inflorescences.

5. Inflorescences with large sterile flowers and numerous small fertileflowers.

Plants of the new Hydrangea differ from plants of parent selections andother selections of Hydrangea arborescens known to the inventor in thefollowing characteristics:

1. Plants of the new Hydrangea are taller and more vigorous than otherknown selections of Hydrangea arborescens known to the inventor.

2. Plants of the new Hydrangea are more freely branching than otherselections of Hydrangea arborescens known to the inventor.

3. Plants of the new Hydrangea have larger, healthier and more durablefoliage than other selections of Hydrangea arborescens known to theinventor.

4. Plants of the new Hydrangea have larger inflorescences with moreflowers per inflorescence than other selections of Hydrangea arborescensknown to the inventor.

Plants of the new Hydrangea can be compared to plants of the Hydrangeaarborescens cultivar Annabelle, not patented. In side-by-sidecomparisons conducted in Grand Haven, Mich., plants of the new Hydrangeadiffered from plants of the cultivar Annabelle in the followingcharacteristics:

1. Plants of the new Hydrangea were taller and more vigorous than plantsof the cultivar Annabelle.

2. Plants of the new Hydrangea were more freely branching than plants ofthe cultivar Annabelle.

3. Plants of the new Hydrangea had stronger stems than plants of thecultivar Annabelle.

4. Plants of the new Hydrangea had broader, healthier and more durablefoliage than plants of the cultivar Annabelle.

5. Plants of the new Hydrangea had dome-shaped inflorescences whereasplants of the cultivar Annabelle had globose-shaped inflorescences.

6. Plants of the new Hydrangea were more freely flowering than plants ofthe cultivar Annabelle.

7. Flowers of plants of the new Hydrangea were mostly fertile whereasflowers of plants of the cultivar Annabelle were mostly sterile.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance ofthe new cultivar, showing the colors as true as it is reasonablypossible to obtain in colored reproductions of this type. Colors in thephotographs may differ from the color values cited in the detailedbotanical description which accurately describe the colors of the newHydrangea.

The photograph at the top of the sheet is a close-up view of ainflorescence of a typical plant of ‘Dardom’.

The photograph at the bottom of the sheet comprises a side perspectiveview of a typical plant of ‘Dardom’ grown in the landscape.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The RoyalHorticultural Society Colour Chart, 1995 Edition, except where generalterms of ordinary dictionary significance are used. Plants used in theaforementioned photographs and in the following description were grownin Grand Haven, Mich., in ground beds in an outdoor nursery and underconditions which closely approximate commercial production conditions.Plants were about three years old when the photographs and descriptionwere taken. The photographs and description were taken during latespring and early summer.

Botanical classification: Hydrangea arborescens cultivar Dardom.

Parentage:

Male, or pollen, parent.—Unidentified Hydrangea arborescens selection,not patented.

Female, or seed, parent.—Unidentified Hydrangea arborescens selection,not patented.

Propagation:

Type cutting.—By softwood cuttings.

Time to initiate roots.—About 10 days at 25° C.

Time to produce a rooted cutting or liner.—About 70 days at 25° C.

Root description.—Fine; cream-colored.

Rooting habit.—Freely branching.

Plant description:

Form/growth habit.—Upright and rounded plant habit; bushy perennialshrub. Tall and vigorous.

Usage.—Appropriate for one to three-gallon containers.

Plant height, soil level to top of plant.—About 150 cm.

Plant diameter or area of spread.—About 100 cm.

Branching habit.—When pinched, freely branching with potentially about99 lateral branches per plant.

Lateral branches.—Length: About 100 cm. Diameter: About 7 mm. Internodelength: About 18 cm. Texture: Glabrous. Color: 146C.

Foliage description.—Leaves large, simple, opposite and durable.Quantity per lateral branch: Typically about 22. Length: About 16 cm.Width: About 13.5 cm. Shape: Broadly ovate. Apex: Obtuse to acute. Base:Cordate to obtuse. Margin: Dentate to serrate. Texture: Upper surface:Glabrous. Lower surface: Slightly pubescent. Venation pattern: Pinnate.Color: Young foliage, upper surface: 146A. Young foliage, lower surface:196A. Mature foliage, upper surface: 136A. Mature foliage, lowersurface: 191A. Venation, upper surface: 136C. Venation, lower surface:191B. Petiole: Length: About 7 cm. Diameter: About 4 mm. Color: 146B.

Flower description:

Flower type and habit.—Single fertile and sterile flowers arranged onterminal corymbs; corymbs large and semi-hemispherical or dome-shaped.Sterile flowers with large showy sepals and without petals andreproductive organs. Fertile flowers with petals, sepals andreproductive organs. Flowers persistent. Inflorescences slightlyfragrant.

Natural flowering season.—Continuously flowering from early July tomid-August in Grand Haven, Mich.

Flower longevity.—Sterile flowers last about six weeks on the plant;fertile flowers last about five weeks on the plant.

Quantity of flowers.—Freely flowering; about 16 sterile flowers andabout 1863 fertile flowers per corymb.

Corymb diameter.—About 20 cm by 15 cm.

Corymb height.—About 10 cm.

Flower diameter.—Fertile flowers: About 3 to 4 mm. Sterile flowers:About 2 cm.

Flower depth (height).—Fertile flowers: About 2 to 3 mm. Sterileflowers: About 3 mm.

Flower buds (fertile and sterile flowers).—Length: About 2 mm. Diameter:About 2 mm. Shape: Obovate. Color: 144B.

Petals (petals present only on fertile flowers; sterile flowers do nothave petals).—Arrangement: About five. Length: About 3 mm. Width: About2 mm. Shape: Lanceolate. Apex: Acute. Base: Attenuate. Margin: Entire.Texture, upper and lower surfaces: Smooth, glabrous. Color: Whenopening, upper and lower surfaces: 143D. Fully opened, upper and lowersurfaces: 155D.

Sepals.—Quantity per flower: Fertile flowers: About five, fused into acalyx. Sterile flowers: About three or four. Length: Fertile flowers:About 2 mm. Sterile flowers: About 1 cm. Width: Fertile flowers: About 1mm. Sterile flowers: About 8 mm. Shape: Fertile flowers: Connate.Sterile flowers: Ovate. Apex: Fertile flowers: Acute. Sterile flowers:Acute. Base: Fertile flowers: Fused. Sterile flowers: Attenuate. Margin:Fertile flowers: Entire. Sterile flowers: Entire. Texture, fertile andsterile flowers, upper and lower surfaces: Smooth, glabrous. Color:Fertile flowers: When opening and fully opened, upper and lowersurfaces, 144B. Sterile flowers: When opening, upper and lower surfaces:157B. Fully opened, upper and lower surfaces: 155D; color becomingcloser to 143B with subsequent development.

Pedicels.—Angle: Fertile flowers: About 20 to 40° from vertical. Sterileflowers: About 90 to 160° from vertical. Strength, fertile and sterileflowers: Strong. Length, fertile and sterile flowers: About 1.5 cm.Color: Fertile flowers: 144B. Sterile flowers: 155D.

Reproductive organs (reproductive organ present only on fertile flowers;sterile flowers do not have reproductive organs).—Stamens: Quantity perflower: About ten. Anther shape: Round. Anther length: About 1 mm.Anther color: 162D. Pollen amount: Scarce. Pollen color: 155B. Pistils:Pistil quantity per flower: Two, fused. Pistil length: About 1 mm.Stigma shape: Two-lobed. Stigma color: 4D. Style length: About 1 mm.Style color: 4D. Ovary color: 144B. Seed: Minute, dust-like.

Disease/pest resistance: Under commercial production conditions, plantsof the new Hydrangea have not been observed to be resistant to pathogensor pests common to Hydrangea.

Weather tolerance: Plants of the new Hydrangea have been shown to betolerant to temperatures ranging from −30 to 33° C. Flowers of plantshave exhibited excellent tolerance to wind and rain.

It is claimed:
 1. A new and distinct cultivar of Hydrangea plant named‘Dardom’, as illustrated and described.